Health, Tech & Science

Does UV Sanitizing Wand Really Work?

Written by Oliver Liu · 6 min read
UV-sanitizer-wand

Giving the importance of health and safety, there is a wide range of healthcare tools that can be used to improve your overall hygiene and one of them is UV sanitizing wand. The relevancy and efficacy of these products amplify more when you’re suffering from a pandemic.

What is UV Sanitizing Wand?

Ultra-Violet – UV sanitizing wand is a hand-held portable device generally found in homes and uses UV-C light to disinfect the pathogens on the surfaces where it’s exposed. But the question is, does it really work? The answer is usually yes.

There are some limitations and drawbacks to it (discussed later). In research conducted by the American Journal of Infection Control, it is found that the portable wands killed 100% of different types of bacteria just within 5 seconds of exposure to UV-C lights, while inactivated almost 90% of hardy spore-forming bacteria just after 40 seconds.

They claimed the UVC sanitizer device a reasonable alternative in place of the chemicals to disinfect the surfaces. To understand the whole phenomenon let’s discuss the basics.

What does UV light mean?

UV light is a type of naturally occurring electromagnetic radiation in the sunlight with a shorter wavelength i.e. 100nm to 400nm and comprises 10% of total sunlight.

The wavelength of this light is subdivided into three sub-bands, UV-A, UV-B, and UV-C. The UV light with a wavelength less than 290nm i.e. UV-C is considered germicidal (germs killer) but naturally it’s mostly absorbed by our planet’s ozone layer and never reaches the earth.

visible-and-non-visible-light-spectrum

When was UV light invented?

The phenomenon of UV light disinfection has been known for over 140 years since the discovery of Downes and Blunt about the anti-bacterial behavior of shorter wavelengths of light found in the sunlight spectrum.

After the confirmation of UV light’s disinfection ability, the next step is the invention of a technology that replicates the UV light wavelength to disinfect the harmful microbes. So in 1904, the first UV quartz lamp was invented that can produce the wavelength of UV-C lights i.e. 200nm – 280nm, and have disinfection properties.


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How does UV light disinfect?

Germicidal UV-C light can kill up to 99% of pathogens. How? The light energy damages the DNA of pathogens’ cells and causes the modification in its genetic material, and destroys its ability to reproduce. It also causes the formation of harmful substances in the DNA and RNA of microbes, which ultimately results in the mutation of cells that causes the inactivation or cell death of microbes (source).

What is ultraviolet germicidal irradiation (UVGI)?

UVGI is a basic principle of disinfection that is used by the UV sanitizer devices to kill the pathogens with their short wavelength UV-C light and is recommended to use by the United States Army, the CDC, and the Federal Emergency Management Agency (FEMA) for the isolation of disease and bio-defense systems for buildings.

In order to get an effective result, the right dose of UV light must be exposed to the object. The right dose can be classified in terms of irradiance of the UV light. Irradiance can be defined as the dose of a UV light applied on the object at a specific distance for a specific time and is measured in mW/cm2.

What is the basic principle of UV-C light disinfection?

Scientifically the efficiency/credibility of a UV-C sanitizer device is measured in mJ/cm2. Suppose if you’re exposing a UV-C light lamp on an object for 8 seconds whose irradiance is 5mW/cm2 at a specified distance, the delivered dose by the device will be 40 mJ/cm2. A dose of 40 mJ/cm2 is considered a sufficient dose to disinfect the wide range of pathogens i.e. bacteria and viruses including coronavirus (Malayeri, IUVA News 2016).

Does UV light sterilize or disinfect?

It is a myth that either a UV light sterilizes or disinfects pathogens and confused the people to understand the basic strategy of a UV-C sanitizer regarding its effectiveness. To solve this myth, it’s important to understand the difference between sterilization and disinfection.

  • Sterilization:

The process in which all types of microbes are destroyed or eliminated through physical and chemical methods.

  • Disinfection:

The process in which only pathogenic microbes (harmful) or inanimate objects are eliminated.

As per the CDC to avoid the transmission of pathogens, there is no need to sterilize every infected item.  So the UV lights emitted by UV sanitizing wands or other UV sanitizers work on the principle of UVGI and disinfect just pathogenic microbes and ultimately decontamination of the specific site occurs.


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How long does UV light take to disinfect?

In the UVGI process, the time taken by the UV-C sanitizer to disinfect may vary, because there is a relationship found between the size of the microbe’s DNA and the amount of UV radiation exposure. It also depends on the contamination intensity and volume of microbes i.e. how much the specific site is infected by the microbes.

Like in recent days in the pandemic, it takes more time to disinfect the viruses on the mask as compared to normal days. More time will be needed for the surfaces with larger objects or if it is a curvy shape that would require different angles of exposure. All you need, just to understand the phenomenon of UVGI as discussed above and implicate it each time you’re going disinfect any surface with a UV-C light sanitizer wand.

uv-sanitizing-wand

Limitations and drawbacks of a UV sanitizing wand

1. Which one is the best UV sanitizer wand?

As discussed earlier, the UV sanitizer wands emit the UV-C light with wavelength 200nm to 290nm, preferably closer to 260nm. But the important is the irradiance that explains the device’s exposure at a specific distance for a specific time.

Many companies provide the wavelengths of their devices but do not disclose their irradiance, which is needed to determine how an effective dose could be provided to a specific site to kill the pathogen in a reasonable amount of time.

For instance, it makes no sense to purchase a wand with a shorter irradiance, if you will have to move it over an object for an hour. On the other hand, the wand with higher irradiance could cause damage to your skin and eyes while using it. So, in order to get effective results you need to purchase a wand with optimum irradiation.

Another good feature is the presence of a built-in sensor for auto on/off ability, to avoid the exposure of UV lights to the skin.

2. Where does the UV light perform well?

UV light works well on flat and non-porous surfaces. The curve-shaped objects such as face masks require more time and different angles of exposure. When it comes to nooks and crannies, just like the visible light spectrum, UV light also not likely to penetrates there. Dirty and greasy surfaces also reduce the effectiveness of UV light due to low penetration.

3. Scale problem

UV sanitizing wands give the best results on a small scale. If you’ve seen any UV sanitizing unit in a hospital and purchased a UV sanitizing wand by impressing with that, and want to sanitize your whole house or room with just a UV sanitizing wand, then you’re on a mistake.

The hospital unit’s installation is based on a very large setup with professional supervision and authentic clinical-tested UV light devices. But in the case of a UV sanitizing wand, its efficacy is best at small scales such as to disinfect your mobile phone, shoes, or other gadgets.

4. Wands are not very practical

UV sanitizing wands are not likely to consider practical and takes more precautions. In the case of a UV sanitizer box, you can disinfect your mobile, keys, watch, or credit card, etc., with just a little effort. All you need to put the object in the box and leave it for a while (usually 1 to 10 minutes).

uv-sanitizing-box

While in the case of a UV sanitizing wand, you’ve to move the wand repeatedly over the object again and again regarding its specific irradiance to get the maximum efficient results.

5. Training needs to control human error

The chances of human error are also more while using UV sanitizer wands. What if a user holding a wand 1 foot from the surface, while another holding it at a distance of just 3 inches from the same surface. On the other side, what if a user exposes the UV light over an object for just 30 seconds while another holds it for 3 minutes.

So the proper training or practice is needed to get the most effective results regarding UVGI.

6. UV sanitizer wand may affect your skin and eyes

One of the major disadvantages of the UV light sanitizer wand is that its exposure may cause damage to your skin cell and eyes. Its carcinogenic nature can also cause skin cancer. That’s why WHO warns against using it to disinfect your body parts. Again, the use of devices with an internally-lit container such as a UV sanitizer box can play a significant role to avoid the possibility of this danger.

UV-lamp-radiations-disadvantages
Courtesy: World Health Organization
7. Damaging of object

Another drawback of UV light sanitizer is that it may weaken/rupture the components of objects that are exposed to light, such as rubber straps on face masks.

8. FDA approved UV light sanitizer

When there is any doubt regarding healthcare, always trust the health authorities. FDA has not acknowledged the credibility of any UV sanitizing wands till yet. For the most part, if UV lights are being used for things that don’t have medical claims, the FDA does not get involved and expressed risk by using UV light to clean, disinfect, or sanitize devices and accessories.

So is it a wise decision to purchase a UV sanitizing wand?

UV sanitizing wand is a modern and fast-growing technology to disinfect the pathogens and making their worth with time, although more studies with all due aspects have been needed on it like Far-UVC light.

If a UV sanitizing wand contains all of the good features (such as authentic manufacturer, built-in sensors, auto on/off control, irradiance disclosure) then it would be a great tool to disinfect your digital accessories such as mobile, watch, camera, laptop, etc., that cannot be disinfected with traditional methods i.e. with chemical wipes or washing.

But if you’re looking for a complete portable UV disinfection solution for your home or room then we would recommend your mobile UVGI unit over wand due to all the above reasons.

Simple washing – if done well – with a 60% alcohol-based liquid sanitizer can disinfect any surface (either your body or any other object) and provide effective hygiene. But if you’re worried about coronavirus on your countertops, then trust the Centers for Disease Control and Prevention (CDC), which has guidelines for people to disinfect at home.

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